A Case of Cipher's
by ElishevaNadir
Summary: It seems that everyone but Sherlock is riveted by the mysterious cipher's that keep popping up at 221B Baker Street.


Title:_ The Lost Hours: A Case of Ciphers  
><em>Author: Elisheva Nadir

Warnings: Noncanon

AN: I really wanted Mary to pop up in the BBC _Sherlock_ but hopefully she'll make an appearance in the third season. This is how I imagine a modernized Mary in the _Sherlock_ series.

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><p>"Sherlock!" Came Mrs. Hudson's high, breathy voice.<p>

"John, I'm not here," Sherlock said, an arm draped over his eyes as he stretched full length on the couch.

"What? You were just complaining about how you didn't have a case to solve!" John cried incredulously. He rose to his feet, sharing a quick glance with Mary who gave a sympathetic shrug of her shoulders.

"What is it Mrs. Hudson?" John asked, meeting her at the door.

"It's for Sherlock, someone's dropped him a package," Mrs. Hudson said, proffering a yellow packet. Before John could even lift his arm to take the package Sherlock had somehow sprung from the couch and insinuated himself between John and the package, snatching it up.

"They left it at my door by mistake I think," Mrs. Hudson said, moving to stand beside Mary. "Oh, be careful, Sherlock, you don't know what's in that." Headless of Mrs. Hudson's warning, Sherlock grabbed one end of the packet and ripped it open, eagerly pulling out a heavily creased, brightly colored flyer. Any excited light that had been happily dancing behind Sherlock's brilliant blue eyes quickly died as he looked at the message written in bold, black letters:

CYYXIM . CL . LAM . IQYGMY . QP . EHHMY . TEYDMJMB . CGF . GMK . OEMTMI . CI . QGM . QIJQID . TYXGR . GQ . QGM.

"What's it say?" Mary asked, angling her head to try and see the wrinkled piece of paper. Sherlock paused for a handful of seconds before responding dryly with,

"It say's 'Arrive at the corner of Upper Burkeley and New Quebec at one o'clock. Bring no one.'"

"How can you _possibly_ know that?" John asked, astonished.

"Well I'm suitably impressed," Mary said.

"Impressed? Watson, you really must endeavor to find better girlfriends," Sherlock said dryly.

"She's my fiancé, you twat and you'd,"

"Yes, yes, I _know_. But more to the point, the _cipher_," Sherlock said, uttering the word like it was dirt in his mouth, "was easy enough to crack. The letters E, T, and A are the three most common letters in the English language—respectively—followed by O, I, N, S, H, R, D, L, and _U_. The longer the cipher, the easier it becomes to crack it. Patterns of digraphs and trigraphs in the cipher make it nearly child's play but what is most insulting is the need to separate the words from one another, as if it wasn't painfully obvious all ready. There are _two_ double pairs of letters, something like O, O or L, L but because I've all ready deciphered the message I know the first set is R, R and the second set is P, P. This is because the position of the double letters has a higher probability of being consonances rather than vowels. Therefore Y is actually R and H is actually P. The placement of the P's means that E must be U, M is E and Y is R, giving us the word 'upper'. The rest is simple deduction. This particular cipher, instead of relying on a numbered shift, such as moving the code line five spaces to the left or right, is done at random. At least they _tried_ for some modicum of originality." And with that, Sherlock crumpled the bright pink flyer, tossing the wadded paper over his shoulder and verily stormed out of the flat, grabbing his scarf and coat along the way.

"Well," Mrs. Hudson said, "I thought it was rather exciting. Secret packages and the like."

~~_C_~~

Three days later another "cipher" arrived but this time Sherlock was reserved in his manner, unfolding the half sheet of paper with a long suffering sigh before telling the room that it read, "You have one last chance. At noon." He again tossed the crumpled paper over his shoulder and strode out of the flat, apparently to find something to, "Stimulate the mind." No one was under the impression that Sherlock was going to find the mysterious cipher sender but it _was_ rather interesting.

"How do you suppose he figured it out?" Mary asked, picking up the piece of paper and smoothing it out. Written in sloppy but bold handwriting was a five by five row of letters with an N tacked on to the last column.

Y U V E C

O A N T C

H O S N T

E A A A O

L H E N O

_N

"I think," John started to say, looking over her shoulder and reaching past her arm to trace a finger along the letters, "That he went from corner to corner." Mary stared at the rows and then started trying to piece together the "you." Row one, column one was Y. Row two, column one was O. Row one, column two was U. And then Mary saw it. The message ran from corner to corner.

"I don't think I would have seen that for ages," Mary confessed, even though the word "noon" should be—and was—glaringly obvious.

~~_C_~~

A week later from that a third cipher arrived but this time Mary was the only one at 221B Baker Street to watch Sherlock scowl fiercely at the offending bit of paper. He actually looked livid and held the cipher as if he meant to tear it apart but he glanced at Mary and seemed to change his mind.

"Here," Sherlock said, rapidly folding the paper into a plane and flying it at her so he wouldn't have to stand, "Entertain me. Try to figure it out." Mary caught the paper plane, nearly falling off the couch in the process and dumping her stack of under grad papers.

"For heaven's sake!" Mary cried, righting herself and the papers she was meant to be grading. "You said all I had to do was sit here. That I could grade my students papers. Let John look over this when he gets back," Mary said. She had been happily—not really—sitting at her kitchen table and looking through a stack of English essays. Mary really hated first year, introductory courses and it was difficult not to take her purple fountain pen and slash through all the mistakes she found. Which is why she made herself do two read-through's before grading. Compound the fact that Sherlock had called Mary using John's phone to demand she come to 221B Baker Street only made grading the papers worse.

"You have tomorrow to do that," Sherlock said, kicking his feet up on to the coffee table and tipping back in his chair. "I'm bored." Mary scoffed, but unfolded the plane, staring blankly at the list of numbers before her.

9.3/6.3/8.2 - 7.4/4.2/6.3/8.2/5.3/3.1 - 5.3/4.3/7.4/8.1/3.2/6.2 - 8.1/6.3 - 6.1/3.2 - 4.2/6.3/5.3/6.1/3.2/7.4

"You're boredom is not my problem," Mary snapped, dropping the cipher on to the floor and resuming her perusal of some students analysis of cultural practices using _Exodus_ and _The Odyssey_. Seven pages times sixty students was nigh torture as far as Mary was concerned.

"The answer is as plain as the,"

"Sherlock, finish that cliché and I will personally rip your tongue out," Mary snapped. Sherlock had the most dreadful habit of _intentionally_ using overdone cliché's around her. The day she had divulged her position at the university as an adjunct English professor was the same day Sherlock had thrown one literary reference after the other at her, expecting her to know the most obscure quotations. She had explained that that was not how it worked but he refused to believe otherwise. Mary was an English professor, hence professor of all English.

"That's impossible," Sherlock sniffed. "Your hands do not have nearly the strength required to perform such an act." Sherlock swung his legs down, rising to his feet as he smoothed the lapels of his suit jacket.

"Come here and stick your tongue out then," Mary said. Sherlock gave a forced smile, one that was more mocking than anything and looked a great deal like a grimace.

"Humour me," Sherlock begged, moving to stand by Mary so he could snatch up a stack of papers. "I will even make it easier for you and help." Mary let out a cry of protest, reaching out to grab the stack back but Sherlock had moved out of her reach and was scanning the papers, humming in disapproval.

"Dismal." He declared. "Doubly so. F. F. F as well." He snorted in derision, dropping each paper on to the floor as he walked aimlessly about the room.

"Sherlock, stop that! Those are important and I don't want to lose them in your mess," Mary said, looking around and glaring at said mess. Mrs. Hudson was by far and large too lenient of a landlord.

"B? You gave this a B? F! F! Is there anything below an F?" Sherlock was now scribbling on the papers in a fountain pen before sending them to their flight to the floor.

"You bloody well know there isn't anything below an F. Now give those back!" Mary shoved the remaining stack off her lap and hurriedly raced about the limited floor space, gathering up the essays that Sherlock had casually discarded.

"How do these cretins function? It's a waste of resources to let them write let alone think and breathe." Mary managed to gather all of the essays and knocked the remaining ones of out his hands, stooping to grab those as well and hold them tight to her chest. She hoped that he hadn't made a mess of them or that his scrawl was entirely illegible.

"Just stop! Stop touching my things and I promise I will look at the cipher," Mary said, glancing back to the couch. A slow smile spread across Sherlock's mouth, one that he wasn't even bothering to try and hide his smugness about. Mary had the distinct impulse to lash out and punch him in the face.

"Your right arm twitched," Sherlock said with no small amount of satisfaction. "You want to hit me."

"You can take that smirk off your face, this is not the same as when I try to tidy the flat." Mary shuffled the essays back into a somewhat neat stack and returned to the couch, setting the stack aside and taking the cipher up in hand.

Mary stared at the numbers. And stared. And stared a bit longer. She didn't see anything. No pattern or correlation. And it didn't help that Sherlock was standing there, staring at her as he rocked back and forth on his heels, hands clasped behind his back and that insufferable smile still on his face.

"Sherlock, I have no idea what I'm suppose to be doing," Mary confessed, glaring at the numbers. What did they mean?

9.3/6.3/8.2 - 7.4/4.2/6.3/8.2/5.3/3.1 - 5.3/4.3/7.4/8.1/3.2/6.2 - 8.1/6.3 - 6.1/3.2 - 4.2/6.3/5.3/6.1/3.2/7.4

"Is it very tedious living inside your head?" Sherlock asked, rolling as his eyes as he spun away to pace about the room. "Look at the numbers. What do you see?"

"Are you really going to walk me through this like a child?" Mary asked flatly, tracking Sherlock's frenzied steps with narrowed eyes.

"If the shoe,"

"Stop right there. Fine. I'm looking. What am I _seeing_?" Sherlock was nearly bouncing with each step, rushing to stand before her. He looked gleeful now.

"What do you see?"

"I don't know, decimal numbers? Groups of them?"

"_And_?" Mary gave a big sigh and really looked the set of numbers over. They were separated by forward slashes, the first group had three sets of numbers, followed by six, six again, two, two, and six. Two and three went in to six evenly, no chance of gaining a further decimal there. The largest number was nine and the smallest one.

"I… I think that the number before the decimal ranges from two to nine but the number after the decimal only ranges from one to four." Sherlock sunk down to crouch on his toes, arms wrapped around his knees as he intently gazed at Mary.

"What else?" Mary shrugged her shoulders.

"It's not a code for time or coordinates or anything like that so I guess it's meant to be a numerical alphabet but… but it's not a straightforward replacement." Sherlock gave an exasperated sigh and flung himself back, sprawling on the floor and covering his eyes with the bend of his elbow.

"Mary, Mary, Mary," Sherlock admonished. "Are you really going to make me hand you the answer?"

"Sherlock, I'm trying to work through this. Either you want me to do this or not. Now be patient." Sherlock gave her exactly four minutes before he groaned and dug a hand in to his trouser's pocket, fishing out a mobile. Her mobile.

"Were you using this to text?" Mary demanded, catching the airborne mobile and cradling it to her chest.

"Focus. We are cracking a code," Sherlock replied, sitting up on his elbows to stare at Mary. "Have you figured it out? I promise you I could have solved a Rubiks Cube twenty times over in the,"

"I believe the conversation we had followed the rule that you were to keep your nasty comments to yourself," Mary said, looking at her mobile. She compared the cipher to her mobile, wondering how it was suppose to help. Was she suppose to use the internet? Had he programmed a number she was to call and receive the answer?

"Are you done?"

"No," Mary said, sounding a bit defeated. She ran her thumb across the screen which lit up, displaying a touch-screen dialing pad. What did her phone have in common with the cipher? She needed to start there. Her mobile had nine numbers, the cipher's largest number was nine. There was no way the cipher was a secret telephone number, she couldn't imagine pressing that many buttons and actually reaching someone. And even if she did something like press 9 three times and then 6 three times it would still give her absolutely nothing.

"You are over thinking this," Sherlock said. Mary didn't feel like she was thinking at all. She ran her thumb across the screen again, staring at the first decimal then her mobile. The number nine had four letters not three. But… but what if…

Mary grabbed her discarded pen and used her thigh as a table to place the cipher on so she could write over the numbers. The nine _did_ have four numbers but if you looked at the third letter it was a Y, the third letter on six was an O, 8.2 was U and the dash must mean a word separation.

"Finally!" Sherlock cried, shifting to his knees in a graceful glide so he could look down at Mary's work. "It only took the gestation of a gnat but you have finally done it."

"You… should… listen… to… me... holmes," Mary said slowly, substituting the numbers for letters and spelling out the cipher's message. "You should listen to me Holmes? Goodness, I guess that wasn't so difficult."

"Difficult? Calling it child's play would insult children." Sherlock shot to his feet, pacing about the flat as he muttered things to himself.

"Sherlock, this sounds serious. This is the third cipher he's sent you." Sherlock stopped dead, spinning around quickly to stare at Mary.

"What did you say?"

"I said that you need to take this seriously," Mary replied.

"No, tell me exactly what you said."

"I… This sounds serious. This is the third cipher he's sent you," Mary repeated. Sherlock narrowed his gaze, turning his head a fraction to look at the room.

"You think it's a _he_," Sherlock said, practically diving in to the table that was heaped with stacks of old newsprint and magazines. Mary watched him rifle around, seemingly making a greater mess than what had been there.

"Well, it's a man's handwriting," Mary said, glancing down at the cipher.

"You're basing your findings off of stereotypical characteristics of men and women's handwriting," Sherlock said, now crawling along the floor, looking for God only knows what.

"Am I wrong?"

"No, but what you should be noting is that the handwriting is done in a thick, bold marker. Something permanent. The letters are slanted, loosely written and hurriedly scrawled, as if the writer spends a great deal of time having to write things down and quickly. Or perhaps repeatedly. Now think of what type of person—or man—would have to accustom themselves to writing like that. An office worker? Maybe a delivery man? Or it could be," Sherlock suddenly stopped midsentence, shooting to his feet and sparing a moment to give a dark look before shouting, "Wat_son_!" Mary jumped at his cry, watching as Sherlock dropped a fistful of scraps of paper and nearly sprinted out of the flat.

It was shear curiosity that made Mary do it. Made her retrieve the three scraps of paper and lay them side by side. Sherlock had dug out the two previous cipher's and a note. A note from John. One that said something about going to get milk but it was written using a felt tip pen and had partially smeared but the slanted, loose letters were almost an exact match to… Mary sat back and smiled. So John had been playing a prank on Sherlock.

Mary couldn't help but laugh, wanting to see the look on Sherlock's face as he confronted John and the self-satisfied look on John's face as he asked Sherlock what had taken him so long to figure out the sender. Mary couldn't wait for John to arrive back to her flat—there was no way Sherlock would let him have a moments peace at Baker Street—and hear about his little game with Sherlock.

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><p>AN: Hope you enjoyed and sorry if the cipher's are not entirely accurate. I tried my best with them.<p> 


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